Albumin is used to treat patients with severe burns, shock or blood loss. It is also used to supplement media used for growing higher eukaryotic cells and as an excipient for pharmacologically active compounds, many of which need to be stabilised. Albumin fusion proteins are a fusion of a protein to albumin, or to a variant or fragment thereof, and increases the half life of the protein, for example increased in vivo half life. At present albumin is obtained from blood products, such as serum, or produced recombinantly in microogranisms such as yeast or from transgenic plants or animals. The albumin must be purified from the production source in order to provide a product which is sufficiently pure to meet the user's needs and/or to achieve a high yield of product.
A problem with current albumin products is the purification process required. High purity can be achieved but this requires multiple chromatographic purification steps which can be time consuming and/or expensive. For example, the purification process described in WO 2000/044772 comprises a three-step process: cation exchange chromatography followed by anion exchange chromatography followed by dye-binding (affinity) chromatography. Therefore, what is required is a simpler purification process.